Rewrite Markdown rendering function (#276)
Rewrite Markdown rendering function (#276)

* Guards against script injection (as before).
* Can render inline HTML (Previous version strips all HTML tags).
* Uses Array.prototype.forEach instead of dumb for loop.
* Remove use of DOMParser for better performance.
pycontw/pycontw2016,pycontw/pycontw2016,pycontw/pycontw2016,pycontw/pycontw2016